Vein Pattern Management System, Vein Pattern Registration Apparatus, Vein Pattern Authentication Apparatus, Vein Pattern Registration Method, Vein Pattern Authentication Method, Program, and Vein Data Configuration

ABSTRACT

There are provided an imaging unit for capturing an image of a portion of a body surface of a living body with near-infrared light and generating near-infrared light imaging data, a vein pattern extraction unit for extracting a vein pattern from the near-infrared light imaging data by applying a differential filter, which outputs a large value for a pixel having a large difference between the pixel and its surrounding pixel, to a plurality of pixels constituting the near-infrared light imaging data, and a pseudo-vein pattern determination unit for determining presence of a pseudo-vein pattern intentionally formed on a part of the captured body surface based on the extracted vein pattern.

TECHNICAL FIELD

The present invention relates to a vein pattern management system, avein pattern registration apparatus, a vein pattern authenticationapparatus, a vein pattern registration method, a vein patternauthentication method, a program, and a vein data configuration.

BACKGROUND ART

Individual authentication methods include a method for authenticating anindividual by registering a fingerprint, a voiceprint, an iris, and aretina of the individual, or a vein pattern of the back of theindividual's hand or the individual's finger, or the like as registereddata in advance, and verifying and determining data input at the time ofauthentication and the registered data. In particular, individualauthentication using the vein pattern has recently been focused on dueto its high discriminating ability.

For the purpose of improving security of the above-mentioned individualauthentication methods, since it is essential to block illegal usersattempting to impersonate normal authenticated users, methods forblocking such illegal users have been widely developed (for example,refer to Patent Document 1 and Non-Patent Document 1).

PRIOR ART DOCUMENT [Patent Document 1] Japanese Patent ApplicationPublication No. 2005-259345 [Non-Patent Document 1] Tsutomu Matsumoto,“Biometric Authentication in Financial Transactions”, the 9th StudyGroup on Problem of Forged ATM Cards”, Financial Services Agency, Apr.15, 2005

In some individual authentication methods using a vein pattern, the veinpattern is extracted by capturing an image of a backside or a finger ofa hand with near-infrared light and processing extracted imaging datausing a differential filter.

However, since the differential filter used to the imaging data capturedwith the near-infrared light into a vein portion and a non-vein portionis apt to output a pseudo-vein pattern, which has been drawn on a bodysurface with a felt-tip pen and the like, as a vein portion, there is aneed for a method for determining presence of such a pseudo-vein patternin order to avoid impersonation by an illegal user.

The present invention has been made in consideration of theabove-mentioned problems, and an object of the present invention is toprovide a novel and improved vein pattern management system, veinpattern registration apparatus, vein pattern authentication apparatus,vein pattern registration method, vein pattern authentication method,program, and vein data configuration, capable of determining presence ofa pseudo-vein pattern intentionally produced on a body surface.

DISCLOSURE OF THE INVENTION

In order to solve the above problem, according to an embodiment of theinvention, there is provided a vein pattern management system forregistering and authenticating a vein pattern acquired by radiatinglight to a portion of a living body, including: an imaging unit forcapturing an image of a body surface of the portion of the living bodywith near-infrared light and generating near-infrared light imagingdata; a vein pattern extraction unit for extracting a vein pattern fromthe near-infrared light imaging data by applying a differential filter,which outputs a large value for a pixel having a large differencebetween the pixel and its surrounding pixel, to a plurality of pixelsconstituting the near-infrared light imaging data; a pseudo-vein patterndetermination unit for determining presence of a pseudo-vein patternintentionally formed on a part of the captured body surface based on theextracted vein pattern; a vein pattern registration unit for registeringthe near-infrared light vein pattern based on a determination resultfrom the determination unit to generate a registered vein pattern; and avein pattern authentication unit for comparing a newly generatednear-infrared light vein pattern with the registered vein pattern basedon the determination result from the pseudo-vein pattern determinationunit and authenticating the newly generated near-infrared vein pattern,wherein the vein pattern extraction unit calculates a distribution ofoutput values based on acquired output values of the differentialfilter, and the pseudo-vein pattern determination unit determines thepresence of the pseudo-vein pattern based on the distribution of theoutput values.

In order to solve the above problem, according to another embodiment ofthe invention, there is provided a vein pattern registration apparatusincluding: an imaging unit for capturing an image of a body surface of aportion of a living body with near-infrared light and generatingnear-infrared light imaging data; a vein pattern extraction unit forextracting a vein pattern from the near-infrared light imaging data byapplying a differential filter, which outputs a large value for a pixelhaving a large difference between the pixel and its surrounding pixel,to a plurality of pixels constituting the near-infrared light imagingdata; a pseudo-vein pattern determination unit for determining presenceof a pseudo-vein pattern intentionally formed on a part of the capturedbody surface based on the extracted vein pattern; and a vein patternregistration unit for registering the near-infrared light vein patternbased on a determination result from the determination unit to generatea registered vein pattern, wherein the vein pattern extraction unitcalculates a distribution of output values based on acquired outputvalues of the differential filter, and the pseudo-vein patterndetermination unit determines the presence of the pseudo-vein patternbased on the distribution of the output values.

In order to solve the above problem, according to still anotherembodiment of the invention, there is provided a vein patternauthentication apparatus including: an imaging unit for capturing animage of a body surface of a portion of a living body with near-infraredlight and generating near-infrared light imaging data; a vein patternextraction unit for extracting a vein pattern from the near-infraredlight imaging data by applying a differential filter, which outputs alarge value for a pixel having a large difference between the pixel andits surrounding pixel, to a plurality of pixels constituting thenear-infrared light imaging data; a pseudo-vein pattern determinationunit for determining presence of a pseudo-vein pattern intentionallyformed on a part of the captured body surface based on the extractedvein pattern; and a vein pattern authentication unit for comparing thecaptured near-infrared light vein pattern with an already registeredvein pattern and authenticating the captured near-infrared light veinpattern based on a determination result from the pseudo-vein patterndetermination unit, wherein the vein pattern extraction unit calculatesa distribution of output values based on acquired output values of theacquired differential filter, and the pseudo-vein pattern determinationunit determines the presence of the pseudo-vein pattern based on thedistribution of the output values.

The vein pattern extraction unit may further include an outputestimation value calculation unit for calculating an output estimationvalue indicating a ratio of a sum of output values, which are more thana predetermined upper output value, among acquired output values of thedifferential filter relative to a total sum of the acquired outputvalues of the differential filter, and the pseudo-vein patterndetermination unit may determine the presence of the pseudo-vein patternbased on the output estimation value.

The pseudo-vein pattern determination unit may determine that thepseudo-vein pattern is present when the output estimation value is morethan a predetermined threshold value, and determine that the pseudo-veinpattern is not present when the output estimation value is less than thepredetermined threshold value.

The differential filter may be a derivative filter or a Laplacian ofGaussian (Log) filter.

The vein pattern authentication unit may authenticate the near-infraredlight vein pattern based on the registered vein pattern acquired from avein pattern registration apparatus and authenticate the near-infraredlight vein pattern based on the registered vein pattern registeredwithin the vein pattern authentication apparatus.

In order to solve the above problem, according to still anotherembodiment of the invention, there is provided a vein patternregistration method for registering a vein pattern acquired by radiatinglight to a portion of a living body, including the steps of: capturingan image of a body surface of the portion of the living body withnear-infrared light and generating near-infrared light imaging data;extracting a vein pattern from the near-infrared light imaging data togenerate a near-infrared light vein pattern by applying a differentialfilter, which outputs a large value for a pixel having a largedifference between the pixel and its surrounding pixel, to a pluralityof pixels constituting the near-infrared light imaging data; calculatinga distribution of output values based on the output values of thedifferential filter; determining presence of a pseudo-vein patternintentionally formed on a part of the captured body surface based on thecalculated distribution of the output values; and registering the veinpattern as a registered vein pattern based on a determination result.

In order to solve the above problem, according to still anotherembodiment of the invention, there is provided a vein patternauthentication method for authenticating a vein pattern acquired byradiating light to a portion of a living body, including the steps of:capturing an image of a body surface of the portion of the living bodywith near-infrared light and generating near-infrared light imagingdata; extracting a vein pattern from the near-infrared light imagingdata to generate a near-infrared light vein pattern by applying adifferential filter, which outputs a large value for a pixel having alarge difference between the pixel and its surrounding pixel, to aplurality of pixels constituting the near-infrared light imaging data;calculating a distribution of output values based on the output valuesof the differential filter; determining presence of a pseudo-veinpattern intentionally formed on a part of the captured body surfacebased on the calculated distribution of the output values; and comparingan already registered vein pattern with the near-infrared light veinpattern and authenticating the near-infrared light vein pattern based ona determination result.

In the step of calculating a distribution of output values, an outputestimation value indicating a ratio of a sum of output values, which aremore than a predetermined upper output value, may be calculated amongacquired output values of the differential filter relative to a totalsum of the acquired output values of the differential filter.

In the step of determining presence of a pseudo-vein pattern, it may bedetermined that the pseudo-vein pattern is present when the outputestimation value is more than a predetermined threshold value, and itmay be determined that the pseudo-vein pattern is not present when theoutput estimation value is less than the predetermined threshold value.

The differential filter may be a derivative filter or a Laplacian ofGaussian (Log) filter.

In order to solve the above problem, according to still anotherembodiment of the invention, there is provided a program for causing acomputer controlling a vein pattern registration apparatus forregistering a vein pattern acquired by radiating light to a portion of aliving body to execute: an imaging function for capturing an image of abody surface of the portion of the living body with near-infrared lightand generating near-infrared light imaging data; a vein patternextraction function for extracting a vein pattern from the near-infraredlight imaging data by applying a differential filter, which outputs alarge value for a pixel having a large difference between the pixel andits surrounding pixel, to a plurality of pixels constituting thenear-infrared light imaging data and at the same time, calculating adistribution of output values based on acquired output values of thedifferential filter; a pseudo-vein pattern determination function fordetermining presence of a pseudo-vein pattern intentionally formed on apart of the captured body surface based on the distribution of theoutput values for the extracted vein pattern; and a vein patternregistration function for registering the near-infrared light veinpattern based on a determination result to generate a registered veinpattern.

According to this configuration, a computer program is stored in astorage unit included in a computer, and read and executed by CPUincluded in the computer so that the computer program causes thecomputer to operate as the above-mentioned vein pattern registrationapparatus. In addition, there can be also provided a computer readablerecording medium in which the computer program is recorded. Therecording medium may be, for example, a magnetic disk, an optical disk,a magnetic optical disk, a flush memory, and the like. Furthermore, theabove-mentioned computer program may be distributed via a networkwithout using a recording medium.

In order to solve the above problem, according to still anotherembodiment of the invention, there is provided a program for causing acomputer controlling a vein pattern authentication apparatus forauthenticating a vein pattern acquired by radiating light to a portionof a living body to execute: an imaging function for capturing an imageof a body surface of the portion of the living body with near-infraredlight and generating near-infrared light imaging data; a vein patternextraction function for extracting a vein pattern from the near-infraredlight imaging data by applying a differential filter, which outputs alarge value for a pixel having a large difference between the pixel andits surrounding pixel, to a plurality of pixels constituting thenear-infrared light imaging data and at the same time, calculating adistribution of output values based on acquired output values of thedifferential filter; a pseudo-vein pattern determination function fordetermining presence of a pseudo-vein pattern intentionally formed on apart of the captured body surface based on the distribution of theoutput values for the extracted vein pattern; and a vein patternauthentication function for comparing the captured near-infrared lightvein pattern with an already registered vein pattern and authenticatingthe captured near-infrared imaging pattern based on a determinationresult.

According to this configuration, a computer program is stored in astorage unit included in a computer, and read and executed by CPUincluded in the computer so that the computer program causes thecomputer to operate as the above-mentioned vein pattern registrationapparatus. In addition, there can be also provided a computer readablerecording medium in which the computer program is recorded. Therecording medium may be, for example, a magnetic disk, an optical disk,a magnetic optical disk, a flush memory, and the like. Furthermore, theabove-mentioned computer program may be distributed via a networkwithout using a recording medium.

In order to solve the above problem, according to still anotherembodiment of the invention, there is provided a vein data configurationincluding: a vein data storage area containing data that correspond to avein pattern of an individual and are to be verified with image dataacquired by capturing an image of a part of a body surface of a livingbody with near-infrared light; and an output estimation value storagearea containing an evaluated output value indicating a ratio of a sum ofoutput values, which are more than a predetermined upper output value,among output values of a differential filter relative to a total sum ofthe output values of the differential filter for the image data acquiredby capturing the image with the near-infrared light, wherein thedifferential filter is a filter outputting a large value for a pixelhaving a large difference between the pixel and its surrounding pixelfor each pixel constituting the image data acquired by capturing theimage with the near-infrared light.

The vein data configuration may further include a parameter storage areacontaining a parameter changing an output property of the differentialfilter, and the parameter significantly may change an output value ofthe differential filter, when the image data acquired by capturing theimage with the near-infrared light have a difference greater than thatbetween a value indicating a vein portion and a value indicating anon-vein portion.

According to embodiments of the present invention, presence of apseudo-vein pattern intentionally produced on a body surface can bedetermined.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an explanatory diagram illustrating an output value of a Logfilter for a vein pattern;

FIG. 1B is an explanatory diagram illustrating an output value of a Logfilter for a vein pattern;

FIG. 1C is an explanatory diagram illustrating an output value of a Logfilter for a vein pattern;

FIG. 2A is an explanatory diagram illustrating an output value of a Logfilter for a vein pattern;

FIG. 2B is an explanatory diagram illustrating an output value of a Logfilter for a vein pattern;

FIG. 2C is an explanatory diagram illustrating an output value of a Logfilter for a vein pattern;

FIG. 2D is an explanatory diagram illustrating an output value of a Logfilter for a vein pattern;

FIG. 3 is an explanatory diagram illustrating an output valuedistribution of a Log filter;

FIG. 4 is a diagram illustrating a variation of an output estimationvalue of a Log filter;

FIG. 5 is an explanatory diagram illustrating a vein pattern managementsystem according to an embodiment of the present invention;

FIG. 6 is a block diagram illustrating a hardware configuration of avein pattern registration apparatus according to the embodiment;

FIG. 7 is a block diagram illustrating a configuration of the veinpattern registration apparatus according to the embodiment;

FIG. 8 is a block diagram illustrating a configuration of a vein patternauthentication apparatus according to the embodiment;

FIG. 9 is a flowchart illustrating a skeleton extracting methodaccording to the embodiment; and

FIG. 10 is an explanatory diagram illustrating a pseudo-vein patterndrawn on a finger surface.

EXPLANATION OF NUMERAL

-   10 Vein pattern management system-   12 Network-   14 Removable recording medium-   20 Vein pattern registration apparatus-   30 Vein pattern authentication apparatus-   201 CPU-   203 ROM-   205 RAM-   207 BUS-   211 Imaging device-   213 Input device-   215 Output device-   217 Storage device-   219 Drive-   221 Communication device-   231, 301 Imaging unit-   233, 303 Radiation unit-   235, 305 Near-infrared light-   237, 307 Optical lens-   239, 309 Imaging data generation unit-   241, 311 Vein pattern extraction unit-   243, 313 Output estimation value calculation unit-   251, 321 Pseudo-vein pattern determination unit-   261, 331 Vein pattern registration unit-   263, 333 Storage unit-   265 Registered vein pattern disclosure unit

BEST MODE FOR CARRYING OUT THE INVENTION First Embodiment

Hereinafter, preferred embodiments of the present invention will bedescribed in detail with reference to the appended drawings. Note that,in this specification and the appended drawings, structural elementsthat have substantially the same function and structure are denoted withthe same reference numerals, and repeated explanation of thesestructural elements is omitted.

Although, in a later description, the present invention will bedescribed in connection with an example of vein patterns of fingers, thepresent invention is not limited to this example.

<Pseudo-Vein Pattern>

A pseudo-vein pattern intentionally formed on a finger surface will bedescribed as an example of pseudo-vein patterns in preparation for adescription of a vein pattern management system according to a firstembodiment of the present invention.

In biometric authentication with finger vein pattern, althoughimpersonation is difficult because a vein pattern itself is locatedinside of a finger, it is also difficult, in extraction of the veinpattern, to determine whether an extracted vein pattern is locatedinside of the finger. Since a vein per se absorbs near-infrared light,the vein is imaged as a dark shadow while capturing an image of a bodysurface, and if a pseudo-vein pattern is drawn on the body surface witha component, which has absorbency similar to that of the vein, thepseudo-vein pattern might be indistinguishable from the vein pattern.

Since the near-infrared light is permeable to body tissue, on one hand,and is absorbable in hemoglobin in blood (reduced hemoglobin), on theother hand, veins distributed inside of a finger, a palm of a hand, or aback of a hand appear as shadows in an image when the near-infraredlight is radiated to the finger, the palm of the hand, or the back ofthe hand. The shadows of the vein appearing on the image are referred toas a vein pattern.

FIG. 10 is an explanatory diagram illustrating a pseudo-vein patterndrawn on a finger surface. The upper part of FIG. 10 represents a casein which a pseudo-vein pattern is directly drawn on a finger surfacewith a permanent pen, and the lower part of FIG. 9 represents a case inwhich no pseudo-vein patterns are drawn on the finger surface. Inaddition, in either of the upper and lower parts, there are shown fromleft to right a captured image with visible light, a captured image withnear-infrared light, and an image subject to a threshold process of anoutput of a Laplacian of Gaussian (Log) filter that is a kind ofdifferential filters, respectively.

The threshold process as used herein refers to a process in whichpredetermined upper and lower threshold values are assigned to an outputvalue of a Log filter and the output value is set to zero if the outputvalue is less than the lower threshold value and the output value is setto the upper threshold value if the output value is greater than theupper threshold value.

Since an ink component of the permanent pen has a light absorptionproperty similar to that of reduced hemoglobin in a vein, thepseudo-vein pattern drawn with the permanent pen is left in anintermediate image not yet subject to a thinning process as a veinpattern, as shown in top right and bottom right ends of FIG. 10, and isultimately recognized as a vein in the finger.

In order to solve such problems, the inventors of this application hasbeen dedicated to developing so that the inventor has contrived a veinpattern management system, an vein pattern registration apparatus, avein pattern authentication apparatus, a vein pattern registrationmethod, a vein pattern authentication method, a program, and a vein dataconfiguration.

Present Embodiment Output Value of Differential Filter

Referring to FIGS. 1A to 1C, near-infrared light imaging data acquiredby capturing an image of a finger surface with near-infrared light andan output value of a Log filter for a near-infrared light vein patternacquired by extracting a vein pattern from the near-infrared lightimaging data and applying a Log filter, which is a kind of differentialfilters, to the near-infrared light vein pattern, will be described indetail. FIGS. 1A to 1C are explanatory diagrams illustrating an outputvalue of the Log filter for a vein pattern.

FIG. 1A shows near-infrared light imaging data, FIG. 1B shows a Logfilter output for a near-infrared light vein pattern, and FIG. 1C showsa three dimensional representation of the Log filter output. Inaddition, the Log filter output in FIG. 1B has been subject to athreshold process. As shown in FIG. 1A, because the near-infrared lightis absorbable in hemoglobin in blood, a finger vein portion is imaged asa dark shadow in the near-infrared light imaging data. Therefore, theapplication of a differential filter, such as a Log filter, to theimaging data makes it possible to show a clear contrast between thefinger vein portion and others, and to allow the finger vein portion tobe remarkably visible, as shown in FIG. 1B. With reference to the threedimensional representation of the Log filter output shown in FIG. 1C, itcan be seen that the finger vein portion imaged as a white portion inoutput values of the Log filter has output magnitude up to approximately2,000, which is relatively higher than that of the others.

Now referring to FIGS. 2A to 2D, a Log filter output in presence of apseudo-vein pattern on a finger surface will be considered. FIGS. 2A to2D are explanatory diagrams illustrating a Log file output value for avein pattern. FIG. 2A shows a Log filter output in absence of apseudo-vein pattern on a finger surface, and FIG. 2B shows a threedimensional representation of the Log filter output. FIG. 2C shows a Logfilter output in presence of a pseudo-vein pattern on the fingersurface, and FIG. 2D shows a three dimensional representation of the Logfilter output. In FIGS. 2A and 2C, for convenience of comparison, athreshold process has been applied to the Log filter output. To thecontrary, in FIGS. 2B and 2C, there is shown the Log filter output towhich the threshold process has not been applied.

Referring to FIGS. 2C and 2D, it can be seen that the Log filter outputvalue for a portion with the pseudo-vein pattern exceeds approximately18,000 and is remarkably visible relative to a finger vein portion. Thisis because, differently from a vein contained inside of a finger, as thepseudo-vein pattern is formed on the finger surface, a significantlyhigh contrast appears between the pseudo-vein pattern and itssurrounding and the pseudo-vein pattern responds sensitively to a Logfilter.

Based on the above-mentioned knowledge, the inventor of the presentapplication has focused attention on an output value of a differentialfilter, such as a Log filter, so that the inventor has conceived thatpresence of a pseudo-vein pattern formed on a finger surface can bedetected.

FIG. 3 shows a distribution of output values of a Log filter shown inFIGS. 2B and 2D. In FIG. 3, an output value of the Log filter is takenas an abscissa axis and a frequency is taken as an ordinate axis.

As can be seen from FIG. 3, in presence of a pseudo-vein pattern on afinger surface, output values of a Log filter extend close to 20,000,whereas, in absence of the pseudo-vein pattern, the output values of theLog filter extend slightly around 2,000. This means that the presence ofthe pseudo-vein pattern on the finger surface allows the output valuesof the Log filter to reach a very high value and have a remarkablydifferent distribution of output values of a Log filter.

With this point in view, in order to readily estimate a distribution ofoutput values of a differential filter, such as a Log filter, theinventor of the present application has conceived a method of definingan output estimation value of the differential filter, as describedlater, and determining presence of a pseudo-vein pattern based on theoutput estimation value.

The output estimation value of the differential filter is defined asEquation 1 as follows. In Equation 1, v^(thr) represents an upper outputvalue of the differential filter, S(v^(thr)) represents a sum of outputvalues more than the upper output value v^(thr) of the differentialfilter, and r(v^(thr)) represents an output estimation value. Inaddition, S(0) indicates a sum of the output values of the differentialfilter when the upper output value of the differential filter satisfiesv^(thr)=0 and also indicates a simple total sum of the output values ofthe differential filter.

It is noted that the above-mentioned v^(thr) is a value which has beenpreviously set based on an output value distribution of the differentialfilter calculated from a prior determination test or the like usingmultiple estimation data.

$\begin{matrix}{{r\left( v^{thr} \right)} = \frac{S\left( v^{thr} \right)}{S(0)}} & (1)\end{matrix}$

The output estimation value was calculated for the Log filter outputillustrated in FIGS. 2B and 2D, and a result of this calculation isshown in FIG. 4. FIG. 4 is a graph illustrating a variation in theoutput estimation value of the Log filter. In FIG. 4, an upper outputvalue is taken as an abscissa axis and an output estimation value istaken as an ordinate axis.

Referring to FIG. 4, it is appreciated that, in absence of a pseudo-veinpattern, an upper output value is approximately 2,500 and an outputestimation value is approximately 0, whereas, in presence of thepseudo-vein pattern, although the upper output value is 5,000, theoutput estimation value remains large.

As is apparent from FIG. 4, presence of the pseudo-vein pattern can bedetermined by setting the upper output value to approximately 2,500, forexample, and setting the output estimation value to approximately 0.3.It should be noted that a threshold of the upper output value and athreshold of the output estimation value are merely one example and thethreshold of the upper output value may be individually set for eachparticular individual.

(Vein Pattern Management System)

Next, referring to FIG. 5, a vein pattern management system 10 accordingto this embodiment will be described in detail. FIG. 5 is an explanatorydiagram illustrating the vein pattern management system 10 according tothis embodiment.

As shown in FIG. 5, the vein pattern management system 10 include, forexample, a vein pattern registration apparatus 20, and a plurality ofvein pattern authentication apparatuses 30A, 30B, . . . , which areconnected to the vein pattern registration apparatus 20 via a network12.

The network 12 is a communication line network that connects the veinpattern registration apparatus 20 and a vein pattern authenticationapparatus 30 such that they can communicate in either unidirection orbidirection. The network 12 may include, for example, public network,such as Internet, telephone network, satellite communication network, ormulticasting network, private network, such as Wide Area Network (WAN),Local Area Network (LAN), Internet Protocol-Virtual Private Network(IP-VPN), Ethernet (registered trademark), or wireless LAN, and thelike, and is limited neither to wired network nor wireless network.

The vein pattern registration apparatus 20 is operable to radiate lightof a predetermined wavelength to a body surface of an individualdesiring to register his/her vein pattern, capture an image of the bodysurface, extract a vein pattern from the captured image data, andregister the extracted vein pattern as personal identity information.The vein pattern registration apparatus 20 is also operable to determinepresence of a pseudo-vein pattern intentionally formed on the bodysurface and determine whether the extracted vein pattern should beregistered or not. In addition, the vein pattern registration apparatus20 may disclose registered vein patterns, which have been registered asthe personal identity information, as required by the vein patternauthentication apparatus 30 to be described later.

The vein pattern authentication apparatuses 30A and 30B are operable toradiate light of the predetermined wavelength to a body surface of anindividual desiring to register his/her vein pattern, capture an imageof the body surface, extract a vein pattern from the captured imagedata, and compare the extracted vein pattern with already registeredvein patterns to authenticate the individual. The vein patternauthentication apparatus 30 is also operable to determine presence of apseudo-vein pattern intentionally formed on the body surface anddetermine whether the extracted vein pattern should be authenticated ornot. In addition, the vein pattern authentication apparatuses 30A and30B may request the vein pattern registration apparatus 20 to disclosethe already registered vein patterns.

It is noted that the vein pattern registration apparatus 20 and the veinpattern authentication apparatus 30A and 30B may be connected via thenetwork 12 as shown in the figures, or may be directly connected via aUniversal Serial Bus (USB) port, an IEEE 1394 port, such as an i.LINK, aSmall Computer System Interface (SCSI) port, a RS-232C port, or thelike, not via the network 12.

Although, in FIG. 5, there is only one vein pattern registrationapparatus 20 connected to a network 12, this embodiment is not intendedto be limited to a configuration as described above, but may allow aplurality of vein pattern registration apparatuses 20 to be connected onthe network 12. Similarly, in FIG. 5, there are only two vein patternauthentication apparatuses 30 which are connected to the network 12, anda plurality of vein pattern authentication apparatuses 30 may beconnected on the network 12.

(Configuration of Vein Pattern Registration Apparatus 20)

Referring to FIG. 6, a hardware configuration of a vein patternregistration apparatus 20 according to this embodiment will be describedin detail. FIG. 6 is a block diagram illustrating the hardwareconfiguration of the vein pattern registration apparatus 20 according tothis embodiment.

As shown in FIG. 6, the vein pattern registration apparatus 20 mainlyincludes Central Processing Unit (CPU) 201, Read Only Memory (ROM) 203,Random Access Memory (RAM) 205, a bus 207, an imaging device 211, aninput device 213, an output device 215, a storage device 217, a drive219, and a communication device 221.

CPU 201 serves as a computing device and a controller for controllingall or a part of operations in the vein pattern registration apparatus20 in accordance with various programs recorded in ROM 203, RAM 205, thestorage device 217 or a removable recording medium 14. ROM 203 storesprograms, operational parameters, and the like used by CPU 201. RAM 205temporarily stores a program for use in execution by CPU 201, parametersthat change appropriately in the execution of the program, and the like.CPU, ROM, and RAM are connected with each other via the bus 207 formedby an internal bus, such as a CPU bus.

The imaging device 211 is a device that captures an image of a bodysurface to generate image data under control of CPU 201. The imagingdevice 211 includes, for example, a radiation device for radiating lightof a predetermined wavelength and a focusing device, such as an opticallens, for focusing light transmitting through the body surface. Theradiation device includes a light source emitting the light of thepredetermined wavelength and radiates the light of the predeterminedwavelength based on a control signal from CPU 201. The focusing devicecollects the light radiated from the radiation device and generates theimage data.

The input device 213 includes, for example, an operation means, such asmouse, a keyboard, a touch panel, a button, a switch, and a lever, whichis operated by a user, and an audio input means, such as a microphoneand a headset. In addition, the input device 213 may be, for example, aremote control means (what is called remote controller) using infraredradiation or other radio waves, or may be an external connection device,such as a mobile telephone and PDA, adapted to the operation of the veinpattern registration apparatus 20. Furthermore, the input device 213 mayinclude, for example, an input control circuit or the like, forgenerating an input signal based on information input by the user usingthe above-mentioned operation means and audio input means and outputtingthe input signal to CPU 201. The user of the vein pattern registrationapparatus 20 can input various data and instruct a processing operationto the vein pattern registration apparatus 20 by operating the inputdevice 213.

The output device 215 includes, for example, a display device, such as aCathode Ray Tube (CRT) display device, a Liquid Crystal Display (LCD)device, a Plasma Display Panel (PDP) device, an Electro-Luminescence(EL) display device and a lamp, an audio output device, such as aspeaker and head phones, a printer, a mobile phone, a facsimile machine,and the like, which are capable of visually or audibly communicatingacquired information to the user.

The storage device 217 is a data storing device, which is configured asan example of a storage unit of the vein pattern registration apparatus20 according to this embodiment, and includes, for example, a magneticstorage device, such as a hard disk drive (HDD), a semiconductor storagedevice, an optical storage device, a magnetic optical storage device, orthe like. The storage device 217 stores a wide variety of data, such asprograms executed by CPU 201, various data, and various types of dataacquired from an outside.

The drive 219 is a reader/writer for a storing medium and may beembedded in or attached externally to the vein pattern registrationapparatus 20. The drive 219 reads out information recorded in theremovable recording medium 14, such as an attached magnetic disk,optical disk, magnetic optical disk, or semiconductor memory, andoutputs the information to RAM 205. In addition, the drive 219 iscapable of writing recordings to the removable recording medium 14, suchas the attached magnetic disk, optical disk, magnetic optical disk, orsemiconductor memory. The removable recording medium 14 includes, forexample, a DVD medium, a HD-DVD medium, a Blu-ray medium, CompactFlash(CF) (registered trademark), a memory stick, a Secure Digital (SD)memory card, or the like. In addition, the removable recording medium 14may be, for example, in a form of an Integrated Circuit (IC) cardequipped with a non-contact IC chip, an electronic device, or the like.

The communication device 221 is a communication interface, whichinclude, for example, a communication device for connecting to acommunication network 12. The communication device 221 is made in a formof a communication card for use in wired or wireless Local Area Network(LAN), Bluetooth, or Wireless USB (WUSB), a router for use in opticalcommunication, a router for use in Asymmetric Digital Subscriber Line(ADSL), a modem for use in various communication environments, or thelike. This communication device 221 is capable of sending/receivingsignals and the like to/from other vein pattern registration devices 20and other vein pattern authentication devices 30. In addition, thenetwork 12 connected to the communication device 221 is formed bynetworks and the like connected via wired or wireless connection, andmay be configured, for example, as Internet, home LAN, infraredcommunication, satellite communication, or the like.

With a configuration as described above, the vein pattern registrationapparatus 20 can radiate light of a predetermined wavelength to a bodysurface of an individual desiring to register his/her vein pattern,capture an image of the body surface, extract a vein pattern from thecaptured image data, and register the extracted vein pattern as personalidentity information. In addition, the vein pattern registrationapparatus 20 can send/receive data to/from the vein patternauthentication apparatus 30 directly connected to the vein patternregistration apparatus 20 or the vein pattern authentication apparatus30 connected to the network 12, and retrieve information stored in thevein pattern registration apparatus 20 using the removable recordingmedium 14.

An example of a possible hardware configuration for implementingfunctions of vein pattern registration apparatus 20 according to thisembodiment has been described above. Each of the above components may beconfigured using a general purpose member, or may be configured with adedicated hardware for a function of each component. Thus, the hardwareconfiguration used herein can be appropriately modified depending onstate of the art at the time of implementing this embodiment.

A description of a hardware configuration of the vein patternauthentication apparatus 30 is omitted, since the hardware configurationof the vein pattern authentication apparatus 30 is substantiallyidentical to that of the vein pattern registration apparatus 20.

Next, referring to FIG. 7, a configuration of a vein patternregistration apparatus 20 according to this embodiment will be describedin detail. FIG. 7 is a block diagram illustrating the configuration ofthe vein pattern registration apparatus 20 according to this embodiment.

As shown in FIG. 7, the vein pattern registration apparatus 20 accordingto this embodiment includes, for example, an imaging unit 231, a veinpattern extraction unit 241, a pseudo-vein pattern determination unit251, a vein pattern registration unit 261, a storage unit 263, and aregistered vein pattern disclosure unit 265.

The imaging unit 231 captures an image of a body surface H of anindividual desiring to register his/her vein pattern and generatesimaging data. The imaging unit 231 includes, for example, a radiationunit 233 radiating light of a predetermined wavelength, an optical lens237 focusing light transmitting through the body surface H, and animaging data generation unit 239 generating imaging data based on thefocused light.

The radiation unit 233 includes a light source, such as a halogen lampand a light emitting diode, which radiates near-infrared light to thebody surface H and radiates near-infrared light 235 having a wavelengthof about 600 nm to about 1,300 nm.

The optical lens 237 focuses the near-infrared light 235 transmittingthrough the body surface H, such as a finger surface, and forms an imageon the imaging data generation unit 239. The optical lens 237 accordingto this embodiment is capable of focusing the near-infrared light 235 bychanging a magnification to a predetermined magnification. In order tofocus the near-infrared light 235 to form an image at variousmagnifications, the optical lens 237 according to this embodiment mayinclude multiple optical lenses having different focal lengths,respectively, or may include a multifocal lens having a variable focallength.

The imaging data generation unit 239 generates near-infrared lightimaging data of various magnifications based on transmitted light of thenear-infrared light 235, which has been focused by the optical lens 237.The imaging data generation unit 239 includes, for example, a ChargeCoupled Device (CCD) image sensor, a Complementary-Metal OxideSemiconductor (C-MOS) image sensor, or the like and outputs thenear-infrared light imaging data to the vein pattern extraction unit 241to be described later. In addition, the imaging data generation unit 239may store the generated near-infrared light imaging data in the storageunit 273 to be described later. In storing in the storage unit 273, dateof capture or time of capture may be associated to the generatednear-infrared light imaging data. Furthermore, the generatednear-infrared light imaging data may be in the form of a Red-Green-Blue(RGB) signal or may be image data of other colors, gray scale imagedata, or the like.

The vein pattern extraction unit 241 includes, for example, a functionof performing a pre-process for vein pattern extraction on thenear-infrared light imaging data transmitted from the imaging datageneration unit 239, a function of extracting a vein pattern, and afunction of performing a post-process for the vein pattern extraction.

The pre-process for the vein pattern extraction includes, for example, aprocess for detecting a contour of a finger from near-infrared lightimaging data and discriminating where the finger is located in thenear-infrared light imaging data, a process for rotating thenear-infrared light imaging data using the detected contour of thefinger and correcting an angle of the near-infrared light imaging data(an angle of captured image), and the like.

In addition, the vein pattern extraction may be achieved by applying adifferential filter to the near-infrared light imaging data, which hasbeen subject to detecting the contour or correcting the angle. Thedifferential filter is a filter that outputs a high value as an outputvalue for an image of interest and its surrounding pixels at a portionwhere differences between the pixel of interest and its surroundingpixels, respectively, are large. In other words, the differential filteras used herein refers to a filter that enhances a line or an edge in animage by an operation using differences in gray level values between apixel of interest and its surroundings.

In general, performing a filtering process on image data u(x, y) with avariable, which is a lattice point (x, y) on a two-dimensional plane,using a filter h(x, y) results in image data v(x, y), as shown in thefollowing Equation 2. In the following Equation 2, * denotesconvolution.

$\begin{matrix}\begin{matrix}{{v\left( {x,y} \right)} = {{u\left( {x,y} \right)}*{h\left( {x,y} \right)}}} \\{= {\sum\limits_{m_{1}}{\sum\limits_{m_{2}}{{h\left( {m_{1},m_{2}} \right)}{u\left( {{x - m_{1}},{y - m_{2}}} \right)}}}}} \\{= {\sum\limits_{m_{1}}{\sum\limits_{m_{2}}{{u\left( {m_{1},m_{2}} \right)}{h\left( {{x - m_{1}},{y - m_{2}}} \right)}}}}}\end{matrix} & (2)\end{matrix}$

In the vein pattern extraction according to this embodiment, aderivative filter, such as a first order spatial derivative filter or asecond order spatial derivative filter may be used as theabove-mentioned differential filter. The first order spatial derivativefilter refers to a filter that, for a pixel of interest, calculates adifference in gray scale levels between the pixel of interest and itshorizontally adjacent pixel or its vertically adjacent pixel, and thesecond order spatial derivative filter refers to a filter that extractsa portion having an increased variation in differences in gray scalevalues for a pixel of interest.

For example, the following Laplacian of Gaussian (Log) filter can beused as the above-mentioned second order spatial derivative filter. TheLog filter (Equation 4) can be written as a second order derivative of aGaussian filter (Equation 3), which is a smoothing filter using a Gaussfunction. In the following Equation 3, σ represents a standard deviationof the Gauss function, in other words, a variable representing a degreeof smoothing for the Gaussian filter. Furthermore, σ in the followingEquation 4 is also a parameter, which represent a standard deviation ofthe Gauss function, as is the case with Equation 3, and changing a valueof σ can cause an output value to change in case of performing a Logfiltering process.

$\begin{matrix}{{h_{gauss}\left( {x,y} \right)} = {\frac{1}{2{\pi\sigma}^{2}}\exp \left\{ {- \frac{\left( {x^{2} + y^{2}} \right)}{2\sigma^{2}}} \right\}}} & (3) \\\begin{matrix}{{h_{Log}\left( {x,y} \right)} = {\nabla^{2}{\cdot {h_{gauss}\left( {x,y} \right)}}}} \\{= {\left( {\frac{\partial^{2}}{\partial x^{2}} + \frac{\partial^{2}}{\partial y^{2}}} \right)h_{gauss}}} \\{= {\frac{\left( {x^{2} + y^{2} - {2\sigma^{2}}} \right)}{2{\pi\sigma}^{6}}\exp \left\{ {- \frac{\left( {x^{2} + y^{2}} \right)}{2\sigma^{2}}} \right\}}}\end{matrix} & (4)\end{matrix}$

Also the above-described post-process for the vein pattern extractionmay include, for example, a threshold process performed on image data,which has been subject to a differential filter, a binarization process,a thinning process, and the like. After having passed through thepost-process, a skeleton of the vein pattern can be extracted.

The vein pattern extraction unit 241 transmits the vein pattern or theskeleton thus extracted to the output estimation value calculation unit243 to be described later. The vein pattern extraction unit 241 may alsostore the extracted vein pattern or skeleton in the storage unit 273 tobe described later. It is noted that the vein pattern extraction unit241 may store a parameter, intermediate results during the processes,and the like, which have been generated to perform each of theabove-mentioned processes, in the storage unit 273.

Furthermore, the vein pattern extraction unit 241 includes an outputestimation value calculation unit 243 for calculating an outputestimation value indicating a ratio of a sum of output values, which aremore than a predetermined upper output value, among acquired outputvalues of the differential filter relative to a total sum of theacquired output values of the differential filter. In this instance theoutput estimation value means a value defined as Equation 5 as follows,and is used in determining whether a pseudo-vein pattern is present ornot.

$\begin{matrix}{{r\left( v^{thr} \right)} = \frac{S\left( v^{thr} \right)}{S(0)}} & (5)\end{matrix}$

In Equation 5, v^(thr) represents an upper output value of thedifferential filter, S(v^(thr)) represents a sum of output values morethan the upper output value v^(thr) of the differential filter, andr(v^(thr)) represents an output estimation value. In addition, S(0)indicates a sum of the output values of the differential filter when theupper output value of the differential filter satisfies v^(thr)=0 andalso indicates a simple total sum of the output values of thedifferential filter.

It is noted that the above-mentioned v^(thr) is a value which has beenpreviously set based on an output value distribution of the differentialfilter calculated from a prior determination test or the like usingmultiple estimation data.

The output estimation value calculation unit 243 may transmit the outputestimation value calculated according to Equation 5, for example, to thepseudo-vein pattern determination unit 251 to be described later. Inaddition, the output estimation value calculation unit 243 may store thecalculated output estimation value in the storage unit 263.

The pseudo-vein pattern determination unit 251 determines presence of apseudo-vein pattern intentionally formed on a part of the body surface Hbased on the output estimation value transmitted from the outputestimation value calculation unit 243 of the vein pattern extractionunit 241. In particular, the pseudo-vein pattern determination unit 251determines the presence of the pseudo-vein pattern by comparing theoutput estimation value transmitted from the output estimation valuecalculation unit 243 with a predetermined threshold value. The thresholdvalue may be, for example, a value which has been previously calculatedfrom a prior determination test or the like using multiple estimationdata or a value unique to a particular individual.

In particular, the pseudo-vein pattern determination unit 251 determinesthat no pseudo-vein patterns have been formed on the part of the bodysurface H when the output estimation value transmitted from the outputestimation value calculation unit 243 is equal to or more than thepredetermined threshold value, and determines that a pseudo-vein patternhas been formed on the part of the body surface H when the outputestimation value is less than the predetermined threshold value.

The pseudo-vein pattern determination unit 251 transmits a determinationresult to the vein pattern registration unit 261. The pseudo-veinpattern determination unit 251 may also store the determination resultin the storage unit 263. Furthermore, in storing in the storage unit263, the vein pattern that has been subject to the determination and thedetermination result may be stored in association with each other.

The vein pattern registration unit 261 registers a generatednear-infrared light vein pattern as a template based on thedetermination result transmitted from the pseudo-vein patterndetermination unit 251. In particular, when the determination result istransmitted from the pseudo-vein pattern determination unit 251,indicating that there is not presence of a pseudo-vein pattern, the veinpattern registration unit 261 stores the near-infrared light veinpattern transmitted from the vein pattern extraction unit 241 as aregistered vein pattern in the storage unit 263. To the contrary, whenthe determination result is transmitted from the pseudo-vein patterndetermination unit 251, indicating that there is presence of apseudo-vein pattern, the vein pattern registration unit 261 does notregister the extracted near-infrared light vein pattern and finishes aregistration process. In registration of the registered vein pattern,not only the near-infrared light vein pattern is stored, but also otherdata for identifying an individual (for example, fingerprint data, faceimage data, iris data, voiceprint data, or the like) having the veinpattern may be stored in association with the near-infrared light veinpattern. Moreover, the registered vein pattern to be registered as thetemplate may contain, for example, header information in conformity to astandard, such as a Common Biometric Exchange File Format (CBEFF)framework.

The storage unit 263 stores a registered vein pattern, which isrequested to be registered from the vein pattern registration unit 261,or other data associated to the registered vein pattern. In addition tothese data, imaging data generated by the imaging data generation unit239, a vein pattern extracted by the vein pattern extraction unit 241,or the like may also be stored. Furthermore, in addition to these data,the vein pattern registration apparatus 20 can cause various parameters,intermediate results, and the like, which are needed to be stored inperforming some processes, or a variety of databases and the like to beappropriately stored. This storing unit 273 can be freely readfrom/written to by the imaging unit 231, vein pattern extraction unit241, pseudo-vein pattern determination unit 251, vein patternregistration unit 261, and the like.

The registered vein pattern disclosure unit 265 may disclose aregistered vein pattern stored in the storage unit 263, for example, asrequired by the vein pattern authentication apparatus 30 connected tothe vein pattern registration apparatus 20.

It is noted that the vein pattern registration apparatus 20 according tothis embodiment may be implemented in various apparatuses, such as aninformation processing apparatus including a computer or a server, amobile terminal or a personal digital assistant (PDA) including a mobiletelephone or PHS, an automated teller machine (ATM), an entrance andexit control apparatus, and the like, for example.

Although in the above description, the registered vein pattern to beregistered as the template has been described in a case of storing thepattern within the vein pattern registration apparatus 20, theregistered vein pattern may be stored in a recording medium, such as DVDmedia, HD-DVD media, Blu-ray media, CompactFlash (registered trademark),memory stick, SD memory card, or the like, an IC card equipped with anon-contact IC chip, an electronic equipment, and the like.

An example of functions of vein pattern registration apparatus 20according to this embodiment has been described above. Each of the abovecomponents may be configured using a general purpose member or circuit,or may be configured with a dedicated hardware for a function of eachcomponent. In addition, a function of each component may be achieved byonly CPU or the like. Thus, a configuration used herein can beappropriately modified depending on state of the art at the time ofimplementing this embodiment.

(Configuration of Vein Pattern Authentication Apparatus 30)

Next, referring to FIG. 8, a configuration of a vein patternauthentication apparatus 30 according to this embodiment will bedescribed in detail. FIG. 8 is a block diagram illustrating theconfiguration of the vein pattern authentication apparatus 30 accordingto this embodiment.

As shown in FIG. 8, the vein pattern authentication apparatus 30according to this embodiment includes, for example, an imaging unit 301,a vein pattern extraction unit 311, a pseudo-vein pattern determinationunit 321, a vein pattern authentication unit 331, and a storage unit333.

The imaging unit 301 captures an image of a body surface H of anindividual desiring to register his/her vein pattern and generatesimaging data. The imaging unit 301 includes, for example, a radiationunit 303 radiating light of a predetermined wavelength, an optical lens307 focusing light transmitting through the body surface H, and animaging data generation unit 309 generating imaging data based on thefocused light.

The radiation unit 303 includes a light source, such as a halogen lampand a light emitting diode, which radiates near-infrared light to thebody surface H and radiates near-infrared light 305 having a wavelengthof about 600 nm to about 1,300 nm.

The optical lens 307 focuses the near-infrared light 305 transmittingthrough the body surface H, such as a finger surface, and forms an imageon the imaging data generation unit 309.

The imaging data generation unit 309 generates near-infrared lightimaging data of various magnifications based on transmitted light of thenear-infrared light 305, which has been focused by the optical lens 307.The imaging data generation unit 309 includes, for example, a CCD imagesensor, a C-MOS image sensor, or the like and outputs the near-infraredlight imaging data to the vein pattern extraction unit 311 to bedescribed later. In addition, the imaging data generation unit 309 maystore the generated near-infrared light imaging data in the storage unit333 to be described later. In storing in the storage unit 333, date ofcapture or time of capture may be associated to the generatednear-infrared light imaging data. Furthermore, the generatednear-infrared light imaging data may be in the form of a Red-Green-Blue(RGB) signal or may be image data of other colors, gray scale imagedata, or the like.

The vein pattern extraction unit 311 includes, for example, a functionof performing a pre-process for vein pattern extraction on thenear-infrared light imaging data transmitted from the imaging datageneration unit 309, a function of extracting a vein pattern, and afunction of performing a post-process for the vein pattern extraction.

The pre-process for the vein pattern extraction includes, for example, aprocess for detecting a contour of a finger from near-infrared lightimaging data and discriminating where the finger is located in thenear-infrared light imaging data, a process for rotating thenear-infrared light imaging data using the detected contour of thefinger and correcting an angle of the near-infrared light imaging data(an angle of captured image), and the like.

In addition, the vein pattern extraction may be achieved by applying adifferential filter to the near-infrared light imaging data, which hasbeen subject to detecting the contour or correcting the angle. Thedifferential filter is a filter that outputs a high value as an outputvalue for a pixel of interest and its surrounding pixels at a portionwhere differences between the pixel of interest and its surroundingpixels, respectively, are large. In other words, the differential filteras used herein refers to a filter that enhances a line or an edge in animage by an operation using differences in gray level values between apixel of interest and its surroundings.

In general, performing a filtering process on image data u(x, y) with avariable, which is a lattice point (x, y) on a two-dimensional plane,using a filter h(x, y) results in image data v(x, y), as shown in thefollowing Equation 6. In the following Equation 6, * denotesconvolution.

$\begin{matrix}\begin{matrix}{{v\left( {x,y} \right)} = {{u\left( {x,y} \right)}*{h\left( {x,y} \right)}}} \\{= {\sum\limits_{m_{1}}{\sum\limits_{m_{2}}{{h\left( {m_{1},m_{2}} \right)}{u\left( {{x - m_{1}},{y - m_{2}}} \right)}}}}} \\{= {\sum\limits_{m_{1}}{\sum\limits_{m_{2}}{{u\left( {m_{1},m_{2}} \right)}{h\left( {{x - m_{1}},{y - m_{2}}} \right)}}}}}\end{matrix} & (6)\end{matrix}$

In the vein pattern extraction according to this embodiment, aderivative filter, such as a first order spatial derivative filter or asecond order spatial derivative filter may be used as theabove-mentioned differential filter. The first order spatial derivativefilter refers to a filter that, for a pixel of interest, calculates adifference in gray scale levels between the pixel of interest and itshorizontally adjacent pixel or its vertically adjacent pixel, and thesecond order spatial derivative filter refers to a filter that extractsa portion having an increased variation in differences in gray scalevalues for a pixel of interest.

For example, the following Laplacian of Gaussian (Log) filter can beused as the above-mentioned second order spatial derivative filter. TheLog filter (Equation 8) can be written as a second order derivative of aGaussian filter (Equation 7), which is a smoothing filter using a Gaussfunction. In the following Equation 7, σ represents a standard deviationof the Gauss function, and in other words a variable representing adegree of smoothing for the Gaussian filter. Furthermore, σ in thefollowing Equation 8 is also a parameter, which represent a standarddeviation of the Gauss function, as is the case with Equation 7, andchanging a value of σ can cause an output value to change in case ofperforming a Log filtering process.

$\begin{matrix}{{h_{gauss}\left( {x,y} \right)} = {\frac{1}{2{\pi\sigma}^{2}}\exp \left\{ {- \frac{\left( {x^{2} + y^{2}} \right)}{2\sigma^{2}}} \right\}}} & (7) \\\begin{matrix}{{h_{Log}\left( {x,y} \right)} = {\nabla^{2}{\cdot {h_{gauss}\left( {x,y} \right)}}}} \\{= {\left( {\frac{\partial^{2}}{\partial x^{2}} + \frac{\partial^{2}}{\partial y^{2}}} \right)h_{gauss}}} \\{= {\frac{\left( {x^{2} + y^{2} - {2\sigma^{2}}} \right)}{2{\pi\sigma}^{6}}\exp \left\{ {- \frac{\left( {x^{2} + y^{2}} \right)}{2\sigma^{2}}} \right\}}}\end{matrix} & (8)\end{matrix}$

Also, the above-described post-process for the vein pattern extractionmay include, for example, a threshold process performed on image data,which has been subject to a differential filter, a binarization process,a thinning process, and the like. After having passed through thepost-process, a skeleton of the vein pattern can be extracted.

The vein pattern extraction unit 311 transmits the vein pattern or theskeleton thus extracted to the output estimation value calculation unit313 to be described later. The vein pattern extraction unit 311 may alsostore the extracted vein pattern or skeleton in the storage unit 333 tobe described later. It is noted that the vein pattern extraction unit311 may store a parameter, intermediate results during the processes,and the like, which have been generated to perform each of theabove-mentioned processes, in the storage unit 333.

In addition, the vein pattern extraction unit 311 further includes anoutput estimation value calculation unit 313 for calculating an outputestimation value indicating a ratio of a sum of output values, which aremore than a predetermined upper output value, among acquired outputvalues of the differential filter relative to a total sum of theacquired output values of the differential filter. In this instance theoutput estimation value means a value defined as Equation 9 as follows,and is used in determining whether a pseudo-vein pattern is present ornot.

$\begin{matrix}{{r\left( v^{thr} \right)} = \frac{S\left( v^{thr} \right)}{S(0)}} & (9)\end{matrix}$

In Equation 9, v^(thr) represents an upper output value of thedifferential filter, S(v^(thr)) represents a sum of output values morethan the upper output value v^(thr) of the differential filter, andr(v^(thr)) represents an output estimation value. In addition, S(0)indicates a sum of the output values of the differential filter when theupper output value of the differential filter satisfies v^(thr)=0 andalso indicates a simple total sum of the output values of thedifferential filter.

It is noted that the above-mentioned v^(thr) is a value which has beenpreviously set based on an output value distribution of the differentialfilter calculated from a prior determination test or the like usingmultiple estimation data.

The output estimation value calculation unit 313 may transmit the outputestimation value calculated according to Equation 9, for example, to thepseudo-vein pattern determination unit 321 to be described later. Inaddition, the output estimation value calculation unit 313 may store thecalculated output estimation value in the storage unit 333.

The pseudo-vein pattern determination unit 321 determines presence of apseudo-vein pattern intentionally formed on a part of the body surface Hbased on the output estimation value transmitted from the outputestimation value calculation unit 313 of the vein pattern extractionunit 311. In particular, the pseudo-vein pattern determination unit 321determines the presence of the pseudo-vein pattern by comparing theoutput estimation value transmitted from the output estimation valuecalculation unit 313 with a predetermined threshold value. The thresholdvalue may be, for example, a value which has been previously calculatedfrom a prior determination test or the like using multiple estimationdata or a value unique to a particular individual.

In particular, the pseudo-vein pattern determination unit 321 determinesthat no pseudo-vein patterns have been formed on the part of the bodysurface H when the output estimation value transmitted from the outputestimation value calculation unit 313 is equal to or more than thepredetermined threshold value, and determines that a pseudo-vein patternhas been formed on the part of the body surface H when the outputestimation value is less than the predetermined threshold value.

The pseudo-vein pattern determination unit 321 transmits a determinationresult to the vein pattern authentication unit 331. The pseudo-veinpattern determination unit 321 may also store the determination resultin the storage unit 333. Furthermore, in storing in the storage unit333, the vein pattern that has been subject to the determination and thedetermination result may be stored in association with each other.

The vein pattern authentication unit 331 performs authentication of agenerated near-infrared light vein pattern based on the determinationresult transmitted from the pseudo-vein pattern determination unit 321.In particular, when the determination result is transmitted from thepseudo-vein pattern determination unit 321, indicating that there is notpresence of a pseudo-vein pattern, for example, the vein patternauthentication unit 331 request the vein pattern registration apparatus20 to disclose a registered vein pattern and compares the registeredvein pattern acquired from the vein pattern registration apparatus 20with the near-infrared light vein pattern transmitted from the veinpattern extraction unit 311. A process of comparing the registered veinpattern with the near-infrared light vein pattern can be achieved, forexample, by calculating a correlation coefficient to be described laterand performing comparison based on the calculated correlationcoefficient. The vein pattern authentication unit 331 authenticates thenear-infrared light vein pattern when a comparison result indicates thatthe registered vein pattern and the near-infrared light vein pattern aresimilar with each other and does not authenticate the near-infraredlight vein pattern when they are not similar with each other.

The correlation coefficient is defined in the following Equation 10, isa statistical measure indicating similarity between two pieces of data:x={x_(i)} and y={y_(i)}, and has a real value from −1 to 1. When thecorrelation coefficient has a value close to 1, it indicates that thetwo pieces of the data are similar with each other, and when thecorrelation coefficient has a value close to 0, it indicates that thetwo pieces of the data are not similar with each other. In addition,when the correlation coefficient has a value close to −1, it indicates acase where the two pieces of the data have inverted signs, respectively.

$\begin{matrix}{r = \frac{\sum\limits_{i}{\left( {x_{i} - \overset{\_}{x}} \right)\left( {y_{i} - \overset{\_}{y}} \right)}}{\sqrt{\sum\limits_{i}\left( {x_{i} - \overset{\_}{x}} \right)^{2}}\sqrt{\sum\limits_{i}\left( {y_{i} - \overset{\_}{y}} \right)^{2}}}} & (10)\end{matrix}$

x: Average of Data x

y: Average of Data y

To the contrary, when the determination result is transmitted from thepseudo-vein pattern determination unit 331, indicating that there ispresence of a pseudo-vein pattern, the vein pattern authentication unit341 does not perform and finishes an authentication process of theextracted near-infrared light vein pattern.

The storage unit 333 is capable of storing imaging data generated by theimaging data generation unit 309, the vein pattern extracted by the veinpattern extraction unit 311, or the like. Furthermore, in addition tothese data, the vein pattern authentication apparatus 30 can causevarious parameters, intermediate results, and the like, which are neededto be stored in performing some processes, or a variety of databases andthe like to be appropriately stored. This storing unit 333 can be freelyread from/written to by the imaging unit 301, vein pattern extractionunit 311, pseudo-vein pattern determination unit 321, vein patternauthentication unit 331, and the like.

The vein pattern authentication apparatus 30 according to thisembodiment may be implemented in various apparatuses, such as aninformation processing apparatus including a computer or a server, amobile terminal or a personal digital assistant (PDA) including a mobiletelephone or PHS, an automated teller machine (ATM), an entrance andexit control apparatus, and the like, for example.

Although in the above description, the registered vein pattern issupposed to be acquired from the vein pattern registration apparatus 20,the authentication may be performed based on the registered veinpattern, which has been stored in a recording medium, such as DVD media,HD-DVD media, Blu-ray media, CompactFlash (registered trademark), memorystick, SD memory card, or the like, an IC card equipped with anon-contact IC chip, an electronic equipment, and the like. Furthermore,the registered vein pattern may be stored in the vein patternauthentication apparatus 30.

An example of functions of vein pattern authentication apparatus 30according to this embodiment has been described above. Each of abovecomponents may be configured using a general purpose member or circuit,or may be configured with a dedicated hardware for a function of eachcomponent. In addition, a function of each component may be achieved byonly CPU or the like. Thus, a configuration used herein can beappropriately modified depending on state of the art at the time ofimplementing this embodiment.

(Registration Method of Vein Pattern)

Next, referring to FIG. 9, a method for registering a vein patternaccording to this embodiment will be described in detail. FIG. 9 is aflowchart illustrating a method for discriminating pseudo-vein patternsaccording to this embodiment.

The method for registering a vein pattern according to this embodimentis characterized in that presence of a pseudo-vein pattern is determinedbased on output values of a differential filter in taking account of adifference in an output value distribution of the differential filterbetween presence and absence of a pseudo-vein pattern.

First, an imaging unit 231 captures an image of a part of a body surface(for example, a finger surface) with near-infrared light 235 and animaging data generation unit 239 in the imaging unit 231 generatesnear-infrared light imaging data (step S101). The imaging datageneration unit 239 stores the generated near-infrared light imagingdata in a storage unit 263, for example, in association with date ofcapture or time of capture, and transmits the generated near-infraredlight imaging data to a vein pattern extraction unit 241.

The vein pattern extraction unit 241, to which the near-infrared lightimaging data transmitted, performs a pre-process for skeleton extractionof a vein pattern on the near-infrared light imaging data, in which thepre-process includes a process for detecting a contour of a finger anddiscriminating a position of the finger, or a process for rotating thenear-infrared light imaging data and correcting an angle of thenear-infrared light imaging data (step S103).

Once the pre-process for the skeleton extraction has finished, the veinpattern extraction unit 241 then calculates a Log filter output byapplying a Log filter process, which is a kind of differential filters,to the near-infrared light imaging data, which has been subject to thepre-process (step S105), and presumes the Log filter output as anear-infrared light vein pattern. After calculating an output value ofthe Log filter, the vein pattern extraction unit 241 stores thecalculated output value of the Log filter (near-infrared light veinpattern) in the storage unit 263.

An output estimation value calculation unit 243 in the vein patternextraction unit 241 calculates an output estimation value based on thecalculated output value of the Log filter after calculating the outputvalue of the Log filter (step S107). In calculation of the estimatedoutput, output values of the Log filter for all pixels constituting thenear-infrared light vein pattern (i.e., gray scale values for respectivepixels) are compared with a predetermined upper output value, and at thesame time, a total sum of the output values of the Log filter for allpixels constituting the near-infrared light vein pattern is calculated.Once a sum of output values of the Log filter, which are more than theupper output value, has been acquired, the output estimation value iscalculated according to the above-mentioned Equation 5. Once the outputestimation value has been calculated, the output estimation valuecalculation unit 243 transmits the calculated output estimation value tothe pseudo-vein pattern determination unit 251. The output estimationvalue calculation unit 243 may also store the calculated outputestimation value in the storage unit 263.

The pseudo-vein pattern determination unit 251 determines whether apseudo-vein pattern is present on a part of a body surface (for example,finger surface) based on the output estimation value transmitted fromthe output estimation value calculation unit 243. Determination ofpresence is performed by determining whether the calculated outputestimation value is equal to or more than a predetermined thresholdvalue or less than the predetermined threshold value (step S109).

On one hand, when the calculated output estimation value is less thanthe predetermined threshold value, the pseudo-vein pattern determinationunit 251 determines that there are no pseudo-vein patterns present onthe finger surface that is subject to imaging, and informs the veinpattern extraction unit 241 and a vein pattern registration unit 261 ofa determination result. The vein pattern extraction unit 241, to whichthe determination result has been informed of, performs a post-process,such a threshold process, a binarization process, and a thinningprocess, on the near-infrared light vein pattern (step S111), and storesthe near-infrared light vein pattern subject to the post-process in thestorage unit 263 as well as transmits the near-infrared light veinpattern to the vein pattern registration unit 261.

On the other hand, when the calculated output estimation value is equalto or more than the predetermined threshold value, the pseudo-veinpattern determination unit 251 determines that there is a pseudo-veinpattern present on the finger surface that is subject to imaging, andinforms the vein pattern registration unit 261 of a determinationresult.

When the vein pattern registration unit 261 is informed of a signalindicating that there are no pseudo-vein patterns present from thepseudo-vein pattern determination unit 251, the vein patternregistration unit 261 stores the near-infrared light vein patternsubject to the post-process and transmitted from the vein patternextraction unit 241 as a registered vein pattern in a database (notshown) contained in the storage unit 263. In addition, the registeredvein pattern may be associated with ID or other biometrics data of anindividual, or the like.

Furthermore, when the vein pattern registration unit 261 is informed ofa signal indicating that there is a pseudo-vein pattern present from thepseudo-vein pattern determination unit 251, the vein patternregistration unit 261 does not perform a registration process of thevein pattern and finishes a series of processes.

As described above, in the method for registering a vein patternaccording to this embodiment, it is possible to determine presence of apseudo-vein pattern intentionally formed on a part of a body surface byfocusing attention on the magnitude or distribution of output values ofa differential filter. Since a method for registering a vein patternaccording to this embodiment can determine presence of a pseudo-veinpattern before registering the vein pattern, possibility of storingunnecessary data in a database and the like, in which registered veinpatterns are contained, is avoided, and it becomes easy to manage theregistered vain patterns.

(Authentication Method of Vein Pattern)

Next, again referring to FIG. 9, a method for authenticating a veinpattern according to this embodiment will be described in detail.

The method for authenticating a vein pattern according to thisembodiment is characterized in that presence of a pseudo-vein pattern isdetermined based on output values of a differential filter in takingaccount of a difference in an output value distribution of thedifferential filter between presence and absence of a pseudo-veinpattern.

First, an imaging unit 301 captures an image of a part of a body surface(for example, a finger surface) with near-infrared light 305 and animaging data generation unit 309 in the imaging unit 301 generatesnear-infrared light imaging data (step S101). The imaging datageneration unit 309 stores the generated near-infrared light imagingdata in a storage unit 333, for example, in association with date ofcapture or time of capture, and transmits the generated near-infraredlight imaging data to a vein pattern extraction unit 311.

The vein pattern extraction unit 311, to which the near-infrared lightimaging data transmitted, performs a pre-process for skeleton extractionof a vein pattern on the near-infrared light imaging data, in which thepre-process includes a process for detecting a contour of a finger anddiscriminating a position of the finger, or a process for rotating thenear-infrared light imaging data and correcting an angle of thenear-infrared light imaging data (step S103).

Once the pre-process for the skeleton extraction has finished, the veinpattern extraction unit 311 then calculates a Log filter output byapplying a Log filter process, which is a kind of differential filters,to the near-infrared light imaging data, which has been subject to thepre-process (step S105), and presumes the Log filter output as anear-infrared light vein pattern. After calculating an output value ofthe Log filter, the vein pattern extraction unit 311 stores thecalculated output value of the Log filter (near-infrared light veinpattern) in the storage unit 333.

An output estimation value calculation unit 313 in the vein patternextraction unit 311 calculates an output estimation value based on thecalculated output value of the Log filter after calculating the outputvalue of the Log filter (step S107). In calculation of the estimatedoutput, output values of the Log filter for all pixels constituting thenear-infrared light vein pattern (i.e., gray scale values for respectivepixels) are compared with a predetermined upper output value, and at thesame time, a total sum of the output values of the Log filter for allpixels constituting the near-infrared light vein pattern is calculated.Once a sum of output values of the Log filter, which are equal to ormore than the upper output value, has been acquired, the outputestimation value is calculated according to the above-mentioned Equation9. Once the output estimation value has been calculated, the outputestimation value calculation unit 243 transmits the calculated outputestimation value to a pseudo-vein pattern determination unit 321. Theoutput estimation value calculation unit 313 may also store thecalculated output estimation value in the storage unit 333.

The pseudo-vein pattern determination unit 321 determines whether apseudo-vein pattern is present on a part of a body surface (for example,finger surface) based on the output estimation value transmitted fromthe output estimation value calculation unit 313. Determination ofpresence is performed by determining whether the calculated outputestimation value is equal to or more than a predetermined thresholdvalue or less than the predetermined threshold value (step S109).

On one hand, when the calculated output estimation value is less thanthe predetermined threshold value, the pseudo-vein pattern determinationunit 321 determines that there are no pseudo-vein patterns present onthe finger surface that is subject to imaging, and informs the veinpattern extraction unit 311 and a vein pattern authentication unit 331of a determination result. The vein pattern extraction unit 331, towhich the determination result has been informed of, performs apost-process, such a threshold process, a binarization process, and athinning process, on the near-infrared light vein pattern (step S111),and stores the near-infrared light vein pattern subject to thepost-process in the storage unit 333 as well as transmits thenear-infrared light vein pattern to the vein pattern authentication unit331.

On the other hand, when the calculated output estimation value is equalto or more than the predetermined threshold value, the pseudo-veinpattern determination unit 321 determines that there is a pseudo-veinpattern present on the finger surface that is subject to imaging, andinforms the vein pattern authentication unit 331 of a determinationresult.

When the vein pattern authentication unit 331 is informed of a signalindicating that there are no pseudo-vein patterns present from thepseudo-vein pattern determination unit 321, the vein patternauthentication unit 331 requests the vein pattern registration apparatus20 to disclose a registered vein pattern. Once the registered veinpattern has been disclosed by a registered vein pattern disclosure unit265 in the vein pattern registration apparatus 20, the vein patternauthentication unit 331 acquires and compares the disclosed registeredvein pattern with the near-infrared light vein pattern, which has beensubject to the post-process, transmitted from the vein patternextraction unit 311. Comparison of the registered vein pattern with thenear-infrared light vein pattern is performed, for example, using amethod capable of quantitatively calculating similarity, such asabove-mentioned correlation coefficient, between image data. The veinpattern authentication unit 331 authenticates the generatednear-infrared light vein pattern when the registered vein pattern andthe near-infrared light vein pattern are similar with each other, butthe vein pattern authentication unit 331 does not authenticate thenear-infrared light vein pattern when they are not similar with eachother.

Furthermore, when the vein pattern authentication unit 331 is informedof a signal indicating that there is a pseudo-vein pattern present fromthe pseudo-vein pattern determination unit 331, the vein patternauthentication unit 321 does not perform an authentication process ofthe vein pattern and finishes a series of processes.

As described above, in the method for authenticating a vein patternaccording to this embodiment, it is possible to determine presence of apseudo-vein pattern intentionally formed on a part of a body surface byfocusing attention on the magnitude or distribution of output values ofa differential filter. Since a method for authenticating a vein patternaccording to this embodiment can determine presence of a pseudo-veinpattern before authenticating the vein pattern, it can previouslyprevent malicious users from impersonating others by repeating try anderror to optimize a pseudo-vein pattern.

(Vein Data Configuration)

Furthermore, according to the present invention, there is provided avein data configuration including a vein data storage area containingdata, which correspond to a vein pattern of an individual and are to beverified with image data acquired by capturing an image of a part of abody surface of a living body with near-infrared light, and an outputestimation value storage area containing an evaluated output value,indicating a ratio of a sum of output values, which are more than apredetermined upper output value, among output values of thedifferential filter relative to a total sum of the output values of thedifferential filter for the image data acquired by capturing the imagewith the near-infrared light.

The vein data storage area is an area containing, for example, a veinpattern that has been registered as a registered vein pattern by thevein pattern registration apparatus 20. The data contained in this veindata storage area are used, for example, by the vein patternauthentication apparatus 30 in authenticating a near-infrared light veinpattern captured.

The output estimation value storage area is an area containing theevaluated output value which indicates the ratio of the sum of theoutput values more than the predetermined upper output value, amongoutput values of the differential filter relative to the total sum ofthe output values of the differential filter for the image data acquiredby capturing the image with the near-infrared light. The outputestimation value contained in this output estimation value storage areaare used, for example, by the vein pattern registration apparatus 20 orthe vein pattern authentication apparatus 30 in determining presence ofa pseudo-vein pattern formed on a body surface.

The above-mentioned vein data configuration further includes a parameterstorage area containing a parameter, which changes an output property ofa differential filter outputting a high output for an pixel that differslargely from its surrounding pixels, for each pixel constituting theimage data acquired by capturing the image with the near-infrared light.

The parameter contained in the parameter storage area is a parameter fora differential filter used, for example, by the vein patternregistration apparatus 20 or the vein pattern authentication apparatus30 in extracting a vein pattern from imaging data captured withnear-infrared light or visible light, and the parameter significantlychanges an output value of the differential filter, for example, whenthe image data acquired by capturing the image with the near-infraredlight have a difference greater than that between a value indicating avein portion and a value indicating a non-vein portion.

The above-mentioned parameter is separately contained for each type ofdifferential filters and makes a pseudo-vein pattern formed on the bodysurface have a value such that the pseudo-vein pattern can be detectedby the differential filter. For example, when a Log filter is used asthe differential filter, a value, by which the Log filter can detect thepseudo-vein pattern, is contained in the parameter storage area. In thiscase, the value of the parameter to be contained is equal to or greaterthan 2.0.

The above-mentioned vein data configuration can be applied to, forexample, a non-contact IC chip, or an IC card, such as a SubscriberIdentity Module (SIM) card, used in a mobile telephone and the like. Inaddition, this vein data configuration can be applied to a recordingmedium, such as a DVD medium, a HD-DVD medium, a Blu-ray medium,CompactFlash (registered trademark), a memory stick, or a SD memorycard.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

For example, although in the above-mentioned embodiments, it has beendescribed that a vein pattern registration apparatus 20 and a veinpattern authentication apparatus 30 are separately provided,respectively, a vein pattern management apparatus including functions ofboth a vein pattern registration apparatus 20 and a vein patternauthentication apparatus 30 may be provided.

Furthermore, although in the above-mentioned embodiments, it has beendescribed that a transmissive imaging unit is provided each of a veinpattern registration apparatus 20 and a vein pattern authenticationapparatus 30, a reflective imaging unit may be provided depending on aportion of a body surface to be captured.

1. A vein pattern management system for registering and authenticating avein pattern acquired by radiating light to a portion of a living body,comprising: an imaging unit for capturing an image of a body surface ofthe portion of the living body with near-infrared light and generatingnear-infrared light imaging data; a vein pattern extraction unit forextracting a vein pattern from the near-infrared light imaging data byapplying a differential filter, which outputs a large value for a pixelhaving a large difference between the pixel and its surrounding pixel,to a plurality of pixels constituting the near-infrared light imagingdata; a pseudo-vein pattern determination unit for determining presenceof a pseudo-vein pattern intentionally formed on a part of the capturedbody surface based on the extracted vein pattern; a vein patternregistration unit for registering the near-infrared light vein patternbased on a determination result from the determination unit to generatea registered vein pattern; and a vein pattern authentication unit forcomparing a newly generated near-infrared light vein pattern with theregistered vein pattern based on the determination result from thepseudo-vein pattern determination unit and authenticating the newlygenerated near-infrared vein pattern, wherein the vein patternextraction unit calculates a distribution of output values based onacquired output values of the differential filter, and the pseudo-veinpattern determination unit determines the presence of the pseudo-veinpattern based on the distribution of the output values.
 2. The veinpattern management system according to claim 1, wherein the vein patternextraction unit further includes an output estimation value calculationunit for calculating an output estimation value indicating a ratio of asum of output values, which are more than a predetermined upper outputvalue, among acquired output values of the differential filter relativeto a total sum of the acquired output values of the differential filter,and the pseudo-vein pattern determination unit determines the presenceof the pseudo-vein pattern based on the output estimation value.
 3. Thevein pattern management system according to claim 2, wherein thepseudo-vein pattern determination unit determines that the pseudo-veinpattern is present when the output estimation value is more than apredetermined threshold value, and determines that the pseudo-veinpattern is not present when the output estimation value is less than thepredetermined threshold value.
 4. The vein pattern management systemaccording to claim 1, wherein the differential filter is a derivativefilter.
 5. The vein pattern management system according to claim 4,wherein the differential filter is a Laplacian of Gaussian (Log) filter.6. A vein pattern registration apparatus comprising: an imaging unit forcapturing an image of a body surface of a portion of a living body withnear-infrared light and generating near-infrared light imaging data; avein pattern extraction unit for extracting a vein pattern from thenear-infrared light imaging data by applying a differential filter,which outputs a large value for a pixel having a large differencebetween the pixel and its surrounding pixel, to a plurality of pixelsconstituting the near-infrared light imaging data; a pseudo-vein patterndetermination unit for determining presence of a pseudo-vein patternintentionally formed on a part of the captured body surface based on theextracted vein pattern; and a vein pattern registration unit forregistering the near-infrared light vein pattern based on adetermination result from the determination unit to generate aregistered vein pattern, wherein the vein pattern extraction unitcalculates a distribution of output values based on acquired outputvalues of the differential filter, and the pseudo-vein patterndetermination unit determines the presence of the pseudo-vein patternbased on the distribution of the output values.
 7. The vein patternregistration apparatus according to claim 6, wherein the vein patternextraction unit further includes an output estimation value calculationunit for calculating an output estimation value indicating a ratio of asum of output values, which are more than a predetermined upper outputvalue, among acquired output values of the differential filter relativeto a total sum of the acquired output values of the differential filter,and the pseudo-vein pattern determination unit determines the presenceof the pseudo-vein pattern based on the output estimation value.
 8. Thevein pattern registration apparatus according to claim 7, wherein thepseudo-vein pattern determination unit determines that the pseudo-veinpattern is present when the output estimation value is more than apredetermined threshold value, and determines that the pseudo-veinpattern is not present when the output estimation value is less than thepredetermined threshold value.
 9. The vein pattern registrationapparatus according to claim 6, wherein the differential filter is aderivative filter.
 10. The vein pattern registration apparatus accordingto claim 9, wherein the differential filter is a Laplacian of Gaussian(Log) filter.
 11. A vein pattern authentication apparatus comprising: animaging unit for capturing an image of a body surface of a portion of aliving body with near-infrared light and generating near-infrared lightimaging data; a vein pattern extraction unit for extracting a veinpattern from the near-infrared light imaging data by applying adifferential filter, which outputs a large value for a pixel having alarge difference between the pixel and its surrounding pixel, to aplurality of pixels constituting the near-infrared light imaging data; apseudo-vein pattern determination unit for determining presence of apseudo-vein pattern intentionally formed on a part of the captured bodysurface based on the extracted vein pattern; and a vein patternauthentication unit for comparing the captured near-infrared light veinpattern with an already registered vein pattern and authenticating thecaptured near-infrared light vein pattern based on a determinationresult from the pseudo-vein pattern determination unit, wherein the veinpattern extraction unit calculates a distribution of output values basedon acquired output values of the acquired differential filter, and thepseudo-vein pattern determination unit determines the presence of thepseudo-vein pattern based on the distribution of the output values. 12.The vein pattern authentication apparatus according to claim 11, whereinthe vein pattern extraction unit further includes an output estimationvalue calculation unit for calculating an output estimation valueindicating a ratio of a sum of output values, which are more than apredetermined upper output value, among acquired output values of thedifferential filter relative to a total sum of the acquired outputvalues of the differential filter, and the pseudo-vein patterndetermination unit determines the presence of the pseudo-vein patternbased on the output estimation value.
 13. The vein patternauthentication apparatus according to claim 12, wherein the pseudo-veinpattern determination unit determines that the pseudo-vein pattern ispresent when the output estimation value is more than a predeterminedthreshold value, and determines that the pseudo-vein pattern is notpresent when the output estimation value is less than the predeterminedthreshold value.
 14. The vein pattern authentication apparatus accordingto claim 11, wherein the differential filter is a derivative filter. 15.The vein pattern authentication apparatus according to claim 14, whereinthe differential filter is a Laplacian of Gaussian (Log) filter.
 16. Thevein pattern authentication apparatus according to claim 11, wherein thevein pattern authentication unit authenticates the near-infrared lightvein pattern based on the registered vein pattern acquired from a veinpattern registration apparatus.
 17. The vein pattern authenticationapparatus according to claim 11, wherein the vein pattern authenticationunit authenticates the near-infrared light vein pattern based on theregistered vein pattern registered within the vein patternauthentication apparatus.
 18. A vein pattern registration method forregistering a vein pattern acquired by radiating light to a portion of aliving body, comprising the steps of: capturing an image of a bodysurface of the portion of the living body with near-infrared light andgenerating near-infrared light imaging data; extracting a vein patternfrom the near-infrared light imaging data to generate a near-infraredlight vein pattern by applying a differential filter, which outputs alarge value for a pixel having a large difference between the pixel andits surrounding pixel, to a plurality of pixels constituting thenear-infrared light imaging data; calculating a distribution of outputvalues based on the output values of the differential filter;determining presence of a pseudo-vein pattern intentionally formed on apart of the captured body surface based on the calculated distributionof the output values; and registering the vein pattern as a registeredvein pattern based on a determination result.
 19. The vein patternregistration method according to claim 18, wherein in the step ofcalculating a distribution of output values, an output estimation valueindicating a ratio of a sum of output values, which are more than apredetermined upper output value, is calculated among acquired outputvalues of the differential filter relative to a total sum of theacquired output values of the differential filter.
 20. The vein patternregistration method according to claim 19, wherein in the step ofdetermining presence of a pseudo-vein pattern, it is determined that thepseudo-vein pattern is present when the output estimation value is morethan a predetermined threshold value, and it is determined that thepseudo-vein pattern is not present when the output estimation value isless than the predetermined threshold value.
 21. The vein patternregistration method according to claim 18, wherein the differentialfilter is a derivative filter.
 22. The vein pattern registration methodaccording to claim 21, wherein the differential filter is a Laplacian ofGaussian (Log) filter.
 23. A vein pattern authentication method forauthenticating a vein pattern acquired by radiating light to a portionof a living body, comprising the steps of: capturing an image of a bodysurface of the portion of the living body with near-infrared light andgenerating near-infrared light imaging data; extracting a vein patternfrom the near-infrared light imaging data to generate a near-infraredlight vein pattern by applying a differential filter, which outputs alarge value for a pixel having a large difference between the pixel andits surrounding pixel, to a plurality of pixels constituting thenear-infrared light imaging data; calculating a distribution of outputvalues based on the output values of the differential filter;determining presence of a pseudo-vein pattern intentionally formed on apart of the captured body surface based on the calculated distributionof the output values; and comparing an already registered vein patternwith the near-infrared light vein pattern and authenticating thenear-infrared light vein pattern based on a determination result. 24.The vein pattern authentication method according to claim 23, wherein inthe step of calculating a distribution of output values, an outputestimation value indicating a ratio of a sum of output values, which aremore than a predetermined upper output value, is calculated amongacquired output values of the differential filter relative to a totalsum of the acquired output values of the differential filter.
 25. Thevein pattern authentication method according to claim 24, wherein in thestep of determining presence of a pseudo-vein pattern, it is determinedthat the pseudo-vein pattern is present when the output estimation valueis more than a predetermined threshold value, and it is determined thatthe pseudo-vein pattern is not present when the output estimation valueis less than the predetermined threshold value.
 26. The vein patternauthentication method according to claim 23, wherein the differentialfilter is a derivative filter.
 27. The vein pattern authenticationmethod according to claim 26, wherein the differential filter is aLaplacian of Gaussian (Log) filter.
 28. A program for causing a computercontrolling a vein pattern registration apparatus for registering a veinpattern acquired by radiating light to a portion of a living body toexecute: an imaging function for capturing an image of a body surface ofthe portion of the living body with near-infrared light and generatingnear-infrared light imaging data; a vein pattern extraction function forextracting a vein pattern from the near-infrared light imaging data byapplying a differential filter, which outputs a large value for a pixelhaving a large difference between the pixel and its surrounding pixel,to a plurality of pixels constituting the near-infrared light imagingdata and at the same time, calculating a distribution of output valuesbased on acquired output values of the differential filter; apseudo-vein pattern determination function for determining presence of apseudo-vein pattern intentionally formed on a part of the captured bodysurface based on the distribution of the output values for the extractedvein pattern; and a vein pattern registration function for registeringthe near-infrared light vein pattern based on a determination result togenerate a registered vein pattern.
 29. A program for causing a computercontrolling a vein pattern authentication apparatus for authenticating avein pattern acquired by radiating light to a portion of a living bodyto execute: an imaging function for capturing an image of a body surfaceof the portion of the living body with near-infrared light andgenerating near-infrared light imaging data; a vein pattern extractionfunction for extracting a vein pattern from the near-infrared lightimaging data by applying a differential filter, which outputs a largevalue for a pixel having a large difference between the pixel and itssurrounding pixel, to a plurality of pixels constituting thenear-infrared light imaging data and at the same time, calculating adistribution of output values based on acquired output values of thedifferential filter; a pseudo-vein pattern determination function fordetermining presence of a pseudo-vein pattern intentionally formed on apart of the captured body surface based on the distribution of theoutput values for the extracted vein pattern; and a vein patternauthentication function for comparing the captured near-infrared lightvein pattern with an already registered vein pattern and authenticatingthe captured near-infrared imaging pattern based on a determinationresult.
 30. A vein data configuration comprising: a vein data storagearea containing data that correspond to a vein pattern of an individualand are to be verified with image data acquired by capturing an image ofa part of a body surface of a living body with near-infrared light; andan output estimation value storage area containing an evaluated outputvalue indicating a ratio of a sum of output values, which are more thana predetermined upper output value, among output values of adifferential filter relative to a total sum of the output values of thedifferential filter for the image data acquired by capturing the imagewith the near-infrared light, wherein the differential filter is afilter outputting a large value for a pixel having a large differencebetween the pixel and its surrounding pixel for each pixel constitutingthe image data acquired by capturing the image with the near-infraredlight.
 31. The vein data configuration according to claim 30, whereinthe vein data configuration further includes a parameter storage areacontaining a parameter changing an output property of the differentialfilter, and the parameter significantly changes an output value of thedifferential filter, when the image data acquired by capturing the imagewith the near-infrared light have a difference greater than that betweena value indicating a vein portion and a value indicating a non-veinportion.